feat(usb_cdc): Add select functionality

components/esp_system/include/esp_private/esp_vfs_cdcacm_select.h

@@ -0,0 +1,31 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#pragma once
+
+#include "freertos/FreeRTOS.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef enum {
+    CDCACM_SELECT_READ_NOTIF,
+    CDCACM_SELECT_WRITE_NOTIF,
+    CDCACM_SELECT_ERROR_NOTIF,
+} cdcacm_select_notif_t;
+
+typedef void (*cdcacm_select_notif_callback_t)(cdcacm_select_notif_t cdcacm_select_notif, BaseType_t *task_woken);
+
+/**
+ * @brief Set notification callback function for select() events
+ * @param cdcacm_select_notif_callback callback function
+ */
+void cdcacm_set_select_notif_callback(cdcacm_select_notif_callback_t cdcacm_select_notif_callback);
+
+#ifdef __cplusplus
+}
+#endif

components/esp_system/include/esp_private/usb_console.h

@@ -1,5 +1,6 @@
+
 /*
- * SPDX-FileCopyrightText: 2019-2022 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2019-2024 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -91,6 +92,15 @@ bool esp_usb_console_write_available(void);
  */
 esp_err_t esp_usb_console_set_cb(esp_usb_console_cb_t rx_cb, esp_usb_console_cb_t tx_cb, void* arg);
 
+/**
+ * @brief Checks whether the USB console is installed or not
+ *
+ * @return
+ *     - true  USB console is installed
+ *     - false USB console is not installed
+ */
+bool esp_usb_console_is_installed(void);
+
 #ifdef __cplusplus
 }
 #endif

components/esp_system/port/usb_console.c

@@ -46,6 +46,8 @@
 #include "esp32s3/rom/usb/chip_usb_dw_wrapper.h"
 #endif
 
+#include "esp_private/esp_vfs_cdcacm_select.h"
+
 #define CDC_WORK_BUF_SIZE (ESP_ROM_CDC_ACM_WORK_BUF_MIN + CONFIG_ESP_CONSOLE_USB_CDC_RX_BUF_SIZE)
 
 typedef enum {
@@ -55,6 +57,7 @@ typedef enum {
     REBOOT_BOOTLOADER_DFU,
 } reboot_type_t;
 
+static bool s_usb_installed = false;
 static reboot_type_t s_queue_reboot = REBOOT_NONE;
 static int s_prev_rts_state;
 static intr_handle_t s_usb_int_handle;
@@ -131,6 +134,18 @@ int esp_usb_console_osglue_wait_proc(int delay_us)
     }
 }
 
+/* USB interrupt handler, forward the call to the ROM driver.
+ * Non-static to allow placement into IRAM by ldgen.
+ */
+static cdcacm_select_notif_callback_t s_cdcacm_select_notif_callback = NULL;
+
+void cdcacm_set_select_notif_callback(cdcacm_select_notif_callback_t cdcacm_select_notif_callback)
+{
+    if (esp_usb_console_is_installed()) {
+        s_cdcacm_select_notif_callback = cdcacm_select_notif_callback;
+    }
+}
+
 /* Called by ROM CDC ACM driver from interrupt context./
  * Non-static to allow placement into IRAM by ldgen.
  */
@@ -168,6 +183,8 @@ void esp_usb_console_dfu_detach_cb(int timeout)
  */
 void esp_usb_console_interrupt(void *arg)
 {
+    BaseType_t xTaskWoken = 0;
+
     usb_dc_check_poll_for_interrupts();
     /* Restart can be requested from esp_usb_console_cdc_acm_cb or esp_usb_console_dfu_detach_cb */
     if (s_queue_reboot != REBOOT_NONE) {
@@ -192,6 +209,21 @@ void esp_usb_console_interrupt(void *arg)
             esp_restart_noos();
         }
     }
+
+    if (esp_usb_console_available_for_read() > 0) {
+        if (s_cdcacm_select_notif_callback != NULL) {
+            s_cdcacm_select_notif_callback(CDCACM_SELECT_READ_NOTIF, &xTaskWoken);
+        }
+    }
+    if (esp_usb_console_write_available()) {
+        if (s_cdcacm_select_notif_callback != NULL) {
+            s_cdcacm_select_notif_callback(CDCACM_SELECT_WRITE_NOTIF, &xTaskWoken);
+        }
+    }
+
+    if (xTaskWoken == pdTRUE) {
+        portYIELD_FROM_ISR();
+    }
 }
 
 /* Called as esp_timer callback when the restart timeout expires.
@@ -299,6 +331,7 @@ esp_err_t esp_usb_console_init(void)
     esp_rom_install_channel_putc(1, &esp_usb_console_write_char);
 #endif // CONFIG_ESP_CONSOLE_USB_CDC_SUPPORT_ETS_PRINTF
 
+    s_usb_installed = true;
     return ESP_OK;
 }
 
@@ -422,6 +455,11 @@ esp_err_t esp_usb_console_set_cb(esp_usb_console_cb_t rx_cb, esp_usb_console_cb_
     return ESP_OK;
 }
 
+bool esp_usb_console_is_installed(void)
+{
+    return s_usb_installed;
+}
+
 ssize_t esp_usb_console_available_for_read(void)
 {
     if (s_cdc_acm_device == NULL) {

components/esp_vfs_console/test_apps/.build-test-rules.yml

@@ -0,0 +1,4 @@
+# Documentation: .gitlab/ci/README.md#manifest-file-to-control-the-buildtest-apps
+components/esp_vfs_console/test_apps/usb_cdc_vfs:
+  enable:
+    - if: IDF_TARGET in ["esp32s3"] # reason: console components is only implemented on these targets. TODO P4: IDF-9120

components/esp_vfs_console/test_apps/usb_cdc_vfs/CMakeLists.txt

@@ -0,0 +1,9 @@
+# This is the project CMakeLists.txt file for the test subproject
+cmake_minimum_required(VERSION 3.5)
+
+list(PREPEND SDKCONFIG_DEFAULTS "$ENV{IDF_PATH}/tools/test_apps/configs/sdkconfig.debug_helpers" "sdkconfig.defaults")
+
+set(COMPONENTS main)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(usb_cdc_vfs_test)

components/esp_vfs_console/test_apps/usb_cdc_vfs/README.md

@@ -0,0 +1,2 @@
+| Supported Targets | ESP32-S3 |
+| ----------------- | -------- |

components/esp_vfs_console/test_apps/usb_cdc_vfs/main/CMakeLists.txt

@@ -0,0 +1,7 @@
+set(src "test_app_main.c")
+
+idf_component_register(SRCS ${src}
+                       PRIV_INCLUDE_DIRS .
+                       PRIV_REQUIRES esp_system esp_vfs_console unity
+                       WHOLE_ARCHIVE
+                       )

components/esp_vfs_console/test_apps/usb_cdc_vfs/main/test_app_main.c

@@ -0,0 +1,96 @@
+/*
+ * SPDX-FileCopyrightText: 2022-2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Unlicense OR CC0-1.0
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/errno.h>
+#include "unity.h"
+#include "esp_private/usb_console.h"
+#include "esp_vfs_cdcacm.h"
+
+static int read_bytes_with_select(FILE *stream, void *buf, size_t buf_len, struct timeval tv)
+{
+    int fd = fileno(stream);
+    fd_set read_fds;
+    FD_ZERO(&read_fds);
+    FD_SET(fd, &read_fds);
+
+    /* call select with to wait for either a read ready or timeout to happen */
+    int nread = select(fd + 1, &read_fds, NULL, NULL, &tv);
+    if (nread < 0) {
+        return -1;
+    } else if (FD_ISSET(fd, &read_fds)) {
+        int read_count = 0;
+        int total_read = 0;
+
+        do {
+            read_count = read(fileno(stream), buf + total_read, 1);
+            if (read_count < 0 && errno != EWOULDBLOCK) {
+                return -1;
+            } else if (read_count > 0) {
+                total_read += read_count;
+                if (total_read > buf_len) {
+                    fflush(stream);
+                    break;
+                }
+            }
+        } while (read_count > 0);
+
+        return total_read;
+    } else {
+        return -2;
+    }
+}
+
+void app_main(void)
+{
+    struct timeval tv;
+    tv.tv_sec = 1;
+    tv.tv_usec = 0;
+    char out_buffer[32];
+    memset(out_buffer, 0, sizeof(out_buffer));
+    size_t out_buffer_len = sizeof(out_buffer);
+
+    // stdin needs to be non blocking to properly call read after select returns
+    // with read ready on stdin.
+    int fd = fileno(stdin);
+    int flags = fcntl(fd, F_GETFL);
+    flags |= O_NONBLOCK;
+    int res = fcntl(fd, F_SETFL, flags);
+    TEST_ASSERT(res == 0);
+
+    // init driver
+    // ESP_ERROR_CHECK(esp_usb_console_init());
+    // esp_vfs_dev_cdcacm_register();
+
+    // send the message from pytest environment and make sure it can be read
+    bool message_received = false;
+    size_t char_read = 0;
+    while (!message_received && out_buffer_len > char_read) {
+        int nread = read_bytes_with_select(stdin, out_buffer + char_read, out_buffer_len - char_read, tv);
+        if (nread > 0) {
+            char_read += nread;
+            if (out_buffer[char_read - 1] == '\n') {
+                message_received = true;
+            }
+        } else if (nread == -2) {
+            // time out occurred, send the expected message back to the testing
+            // environment to trigger the testing environment into sending the
+            // test message. don't update this message without updating the pytest
+            // function since the string is expected as is by the test environment
+            char timeout_msg[] = "select timed out\n";
+            write(fileno(stdout), timeout_msg, sizeof(timeout_msg));
+        } else {
+            break;
+        }
+    }
+
+    // write the received message back to the test environment. The test
+    // environment will check that the message received matches the one sent
+    write(fileno(stdout), out_buffer, char_read);
+
+    vTaskDelay(10); // wait for the string to send
+}

components/esp_vfs_console/test_apps/usb_cdc_vfs/pytest_usb_cdc_vfs.py

@@ -0,0 +1,19 @@
+# SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+# SPDX-License-Identifier: CC0-1.0
+import pytest
+from pytest_embedded import Dut
+
+
+@pytest.mark.esp32s3
+@pytest.mark.usb_device
+@pytest.mark.parametrize(
+    'port, flash_port, config',
+    [
+        pytest.param('/dev/serial_ports/ttyACM-esp32', '/dev/serial_ports/ttyUSB-esp32', 'release'),
+    ],
+    indirect=True,)
+@pytest.mark.parametrize('test_message', ['test123456789!@#%^&*'])
+def test_usb_cdc_vfs_default(dut: Dut, test_message: str) -> None:
+    dut.expect_exact('select timed out', timeout=2)
+    dut.write(test_message)
+    dut.expect_exact(test_message, timeout=2)

components/esp_vfs_console/test_apps/usb_cdc_vfs/sdkconfig.ci.release

@@ -0,0 +1,6 @@
+CONFIG_PM_ENABLE=y
+CONFIG_FREERTOS_USE_TICKLESS_IDLE=y
+CONFIG_COMPILER_OPTIMIZATION_SIZE=y
+CONFIG_BOOTLOADER_COMPILER_OPTIMIZATION_SIZE=y
+CONFIG_COMPILER_OPTIMIZATION_ASSERTIONS_SILENT=y
+CONFIG_COMPILER_OPTIMIZATION_NONE=y

components/esp_vfs_console/test_apps/usb_cdc_vfs/sdkconfig.defaults

@@ -0,0 +1,8 @@
+# Enable Unity fixture support
+CONFIG_UNITY_ENABLE_FIXTURE=n
+CONFIG_UNITY_ENABLE_IDF_TEST_RUNNER=y
+
+# Custom partition table for this test app
+CONFIG_ESP_TASK_WDT_INIT=n
+
+CONFIG_ESP_CONSOLE_USB_CDC=y

components/esp_vfs_console/vfs_cdcacm.c

@@ -15,9 +15,13 @@
 #include "esp_vfs_cdcacm.h"
 #include "esp_attr.h"
 #include "sdkconfig.h"
+#include "esp_heap_caps.h"
 
+#include "esp_private/esp_vfs_cdcacm_select.h"
 #include "esp_private/usb_console.h"
 
+#define USB_CDC_LOCAL_FD 0
+
 // Newline conversion mode when transmitting
 static esp_line_endings_t s_tx_mode =
 #if CONFIG_NEWLIB_STDOUT_LINE_ENDING_CRLF
@@ -38,6 +42,12 @@ static esp_line_endings_t s_rx_mode =
     ESP_LINE_ENDINGS_LF;
 #endif
 
+#if CONFIG_VFS_SELECT_IN_RAM
+#define CDCACM_VFS_MALLOC_FLAGS (MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT)
+#else
+#define CDCACM_VFS_MALLOC_FLAGS MALLOC_CAP_DEFAULT
+#endif
+
 #define NONE -1
 
 //Read and write lock, lazily initialized
@@ -48,6 +58,26 @@ static bool s_blocking;
 static SemaphoreHandle_t s_rx_semaphore;
 static SemaphoreHandle_t s_tx_semaphore;
 
+#ifdef CONFIG_VFS_SUPPORT_SELECT
+
+typedef struct {
+    esp_vfs_select_sem_t select_sem;
+    fd_set *readfds;
+    fd_set *writefds;
+    fd_set *errorfds;
+    fd_set readfds_orig;
+    fd_set writefds_orig;
+    fd_set errorfds_orig;
+} cdcacm_select_args_t;
+
+static cdcacm_select_args_t **s_registered_selects = NULL;
+static int s_registered_select_num = 0;
+static portMUX_TYPE s_registered_select_lock = portMUX_INITIALIZER_UNLOCKED;
+
+static esp_err_t cdcacm_end_select(void *end_select_args);
+
+#endif // CONFIG_VFS_SUPPORT_SELECT
+
 static ssize_t cdcacm_write(int fd, const void *data, size_t size)
 {
     assert(fd == 0);
@@ -82,7 +112,7 @@ static int cdcacm_fsync(int fd)
 
 static int cdcacm_open(const char *path, int flags, int mode)
 {
-    return 0; // fd 0
+    return USB_CDC_LOCAL_FD; // fd 0
 }
 
 static int cdcacm_fstat(int fd, struct stat *st)
@@ -290,6 +320,167 @@ static int cdcacm_fcntl(int fd, int cmd, int arg)
     return result;
 }
 
+#ifdef CONFIG_VFS_SUPPORT_SELECT
+
+static void select_notif_callback_isr(cdcacm_select_notif_t cdcacm_select_notif, BaseType_t *task_woken)
+{
+    portENTER_CRITICAL_ISR(&s_registered_select_lock);
+    for (int i = 0; i < s_registered_select_num; ++i) {
+        cdcacm_select_args_t *args = s_registered_selects[i];
+        if (args) {
+            switch (cdcacm_select_notif) {
+            case CDCACM_SELECT_READ_NOTIF:
+                if (FD_ISSET(USB_CDC_LOCAL_FD, &args->readfds_orig)) {
+                    FD_SET(USB_CDC_LOCAL_FD, args->readfds);
+                    esp_vfs_select_triggered_isr(args->select_sem, task_woken);
+                }
+                break;
+            case CDCACM_SELECT_WRITE_NOTIF:
+                if (FD_ISSET(USB_CDC_LOCAL_FD, &args->writefds_orig)) {
+                    FD_SET(USB_CDC_LOCAL_FD, args->writefds);
+                    esp_vfs_select_triggered_isr(args->select_sem, task_woken);
+                }
+                break;
+            case CDCACM_SELECT_ERROR_NOTIF:
+                if (FD_ISSET(USB_CDC_LOCAL_FD, &args->errorfds_orig)) {
+                    FD_SET(USB_CDC_LOCAL_FD, args->errorfds);
+                    esp_vfs_select_triggered_isr(args->select_sem, task_woken);
+                }
+                break;
+            }
+        }
+    }
+    portEXIT_CRITICAL_ISR(&s_registered_select_lock);
+}
+
+static esp_err_t register_select(cdcacm_select_args_t *args)
+{
+    esp_err_t ret = ESP_ERR_INVALID_ARG;
+
+    if (args) {
+        portENTER_CRITICAL(&s_registered_select_lock);
+        const int new_size = s_registered_select_num + 1;
+        cdcacm_select_args_t **new_selects;
+        if ((new_selects = heap_caps_realloc(s_registered_selects, new_size * sizeof(cdcacm_select_args_t *), CDCACM_VFS_MALLOC_FLAGS)) == NULL) {
+            ret = ESP_ERR_NO_MEM;
+        } else {
+            /* on first select registration register the callback  */
+            if (s_registered_select_num == 0) {
+                cdcacm_set_select_notif_callback(select_notif_callback_isr);
+            }
+
+            s_registered_selects = new_selects;
+            s_registered_selects[s_registered_select_num] = args;
+            s_registered_select_num = new_size;
+            ret = ESP_OK;
+        }
+        portEXIT_CRITICAL(&s_registered_select_lock);
+    }
+
+    return ret;
+}
+
+static esp_err_t unregister_select(cdcacm_select_args_t *args)
+{
+    esp_err_t ret = ESP_OK;
+    if (args) {
+        ret = ESP_ERR_INVALID_STATE;
+        portENTER_CRITICAL(&s_registered_select_lock);
+        for (int i = 0; i < s_registered_select_num; ++i) {
+            if (s_registered_selects[i] == args) {
+                const int new_size = s_registered_select_num - 1;
+                // The item is removed by overwriting it with the last item. The subsequent rellocation will drop the
+                // last item.
+                s_registered_selects[i] = s_registered_selects[new_size];
+                s_registered_selects = heap_caps_realloc(s_registered_selects, new_size * sizeof(cdcacm_select_args_t *), CDCACM_VFS_MALLOC_FLAGS);
+                // Shrinking a buffer with realloc is guaranteed to succeed.
+                s_registered_select_num = new_size;
+
+                /* when the last select is unregistered, also unregister the callback  */
+                if (s_registered_select_num == 0) {
+                    cdcacm_set_select_notif_callback(NULL);
+                }
+
+                ret = ESP_OK;
+                break;
+            }
+        }
+        portEXIT_CRITICAL(&s_registered_select_lock);
+    }
+    return ret;
+}
+
+static esp_err_t cdcacm_start_select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
+                                     esp_vfs_select_sem_t select_sem, void **end_select_args)
+{
+    (void)nfds; /* Since there is only 1 USB OTG, this parameter is useless */
+    *end_select_args = NULL;
+
+    if (!esp_usb_console_is_installed()) {
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    cdcacm_select_args_t *args = heap_caps_malloc(sizeof(cdcacm_select_args_t), CDCACM_VFS_MALLOC_FLAGS);
+
+    if (args == NULL) {
+        return ESP_ERR_NO_MEM;
+    }
+
+    args->select_sem = select_sem;
+    args->readfds = readfds;
+    args->writefds = writefds;
+    args->errorfds = exceptfds;
+    args->readfds_orig = *readfds; // store the original values because they will be set to zero
+    args->writefds_orig = *writefds;
+    args->errorfds_orig = *exceptfds;
+    FD_ZERO(readfds);
+    FD_ZERO(writefds);
+    FD_ZERO(exceptfds);
+
+    esp_err_t ret = register_select(args);
+    if (ret != ESP_OK) {
+        free(args);
+        return ret;
+    }
+
+    bool trigger_select = false;
+    if (FD_ISSET(USB_CDC_LOCAL_FD, &args->readfds_orig) &&
+            esp_usb_console_available_for_read() > 0) {
+
+        // signalize immediately when read is ready
+        FD_SET(USB_CDC_LOCAL_FD, readfds);
+        trigger_select = true;
+    }
+
+    if (FD_ISSET(USB_CDC_LOCAL_FD, &args->writefds_orig) &&
+            esp_usb_console_write_available()) {
+
+        // signalize immediately when write is ready
+        FD_SET(USB_CDC_LOCAL_FD, writefds);
+        trigger_select = true;
+    }
+
+    if (trigger_select) {
+        esp_vfs_select_triggered(args->select_sem);
+    }
+
+    *end_select_args = args;
+    return ESP_OK;
+}
+
+static esp_err_t cdcacm_end_select(void *end_select_args)
+{
+    cdcacm_select_args_t *args = end_select_args;
+    esp_err_t ret = unregister_select(args);
+    if (args) {
+        free(args);
+    }
+
+    return ret;
+}
+
+#endif // CONFIG_VFS_SUPPORT_SELECT
+
 void esp_vfs_dev_cdcacm_set_tx_line_endings(esp_line_endings_t mode)
 {
     s_tx_mode = mode;
@@ -300,6 +491,13 @@ void esp_vfs_dev_cdcacm_set_rx_line_endings(esp_line_endings_t mode)
     s_rx_mode = mode;
 }
 
+#ifdef CONFIG_VFS_SUPPORT_SELECT
+static const esp_vfs_select_ops_t s_cdcacm_vfs_select = {
+    .start_select = &cdcacm_start_select,
+    .end_select = &cdcacm_end_select,
+};
+#endif // CONFIG_VFS_SUPPORT_SELECT
+
 static const esp_vfs_fs_ops_t s_cdcacm_vfs = {
     .write = &cdcacm_write,
     .open = &cdcacm_open,
@@ -307,7 +505,10 @@ static const esp_vfs_fs_ops_t s_cdcacm_vfs = {
     .close = &cdcacm_close,
     .read = &cdcacm_read,
     .fcntl = &cdcacm_fcntl,
-    .fsync = &cdcacm_fsync
+    .fsync = &cdcacm_fsync,
+#ifdef CONFIG_VFS_SUPPORT_SELECT
+    .select = &s_cdcacm_vfs_select,
+#endif // CONFIG_VFS_SUPPORT_SELECT
 };
 
 const esp_vfs_fs_ops_t *esp_vfs_cdcacm_get_vfs(void)